Power machines or vehicles include various work vehicles such as telehandlers, skid steer loaders, tracked loaders, excavators, and utility vehicles. Telehandlers and other power machines typically utilize a hydraulic system including one or more hydraulic pumps that provide pressurized hydraulic fluid to accomplish a number of tasks. Examples of such tasks include powering travel motors in a drive system, positioning a lift arm assembly, rotating implements that may be coupled to the lift arm assembly with respect to the lift arm assembly, and providing hydraulic fluid to actuators on certain implements for performing functions related to the implement, and the like.
Some power machines, including some embodiments of the power machines listed above, have axles that are rigidly mounted to the frame of the machine. As such, they do not have suspension systems between the frame and axles to absorb shock that can be introduced into the power machine when travelling over rough terrain. Some of these power machines utilize the mass of their lift arm assembly and any load that the lift arm assembly may be carrying, which can include attached implements and any material in such an implement, as a suspension system for absorbing such shock. Suspension systems that utilize a lift arm assembly in this manner are known as “ride control systems” or “lift arm suspension systems.” Ride control or lift arm suspension systems include components that selectively allow the lift arm assembly to move up and down slightly when raised above a fully lowered position as the power machine moves over rough terrain, thereby allowing the lift arm assembly to absorb shock and provide a smoother ride for the operator and for the load.
Typical lift arm suspension systems utilize an accumulator to store pressurized hydraulic fluid that aids one or more lift actuators to raise or lower the lift arm assembly slightly as the vehicle traverses the rough terrain, thereby providing ride control. However, under certain conditions in which the accumulator is not sufficiently charged with pressurized hydraulic fluid, a large downward force on the lift arm assembly can force hydraulic fluid from the one or more lift actuators into the accumulator, resulting in an uncommanded lowering of the lift arm assembly.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.